Endocardial mapping apparatus with rotatable arm and method

ABSTRACT

An endocardial mapping apparatus for mapping the wall of a chamber of the heart having blood therein. The apparatus includes a flexible elongate tubular member having proximal and distal extremities and at least one lumen extending therethrough. A basket assembly is carried by the distal extremity of the flexible elongate tubular member and is movable between contracted and expanded positions. The basket assembly has a plurality of elongate flexible circumferentially spaced-apart arms with joined proximal and distal extremities and a plurality of longitudinally spaced-apart electrodes carried by each arm for engaging the wall of the heart. The arms have spaces therebetween when the basket assembly is in an expanded position. An elongate flexible rotatable member is rotatably coupled to the joined distal extremities and is disposed within the basket assembly. At least one electrode is carried by the rotatable member for engaging the wall of the heart. A torque knob is coupled to the rotatable member for rotating the member within the basket assembly and for bowing it radially outwardly into a space between the arms so as to engage the wall of the heart along a portion of the length thereof for mapping and/or ablating.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains generally to medical apparatus for performingendocardial mapping and, more specifically, to endocardial mappingapparatus having a basket assembly with an array of electrodes thereon.

2. Description of Related Art

Catheters have been provided with basket assemblies on the distal endfor performing endocardial mapping. These basket assemblies are formedfrom a plurality of elongate flexible circumferentially-spaced armswhich substantially engage the endocardium and permit blood in the heartto flow therethrough. The arms have a plurality of longitudinally-spacedelectrodes thereon which are electrically connected to a multiplexerchip. In some of these basket assemblies, for example the basketassemblies of application Ser. No. 08/044,255 filed Apr. 7, 1993, U.S.Pat. No. 5,327,889 filed Dec. 1, 1992 and U.S. Pat. No. 5,156,151 filedFeb. 15, 1991, the spacing between the arms is larger than would bedesired for mapping purposes. In addition, there have been difficultiesin effectively ablating with the small low mass electrodes of thesearms. Performing ablations with the mapping electrodes also enhances thecomplication of the multiplexer chip. Because of the foregoing, there isa need for a new and improved endocardial mapping apparatus whichovercomes the above named disadvantages.

OBJECTS OF THE INVENTION

In general, it is an object of the present invention to provide anendocardial mapping apparatus having a basket assembly with a pluralityof expandable arms for engaging the wall of the heart and having arotatable arm which can sense electrical impulses between the arms ofthe basket assembly.

Another object of the invention is to provide a mapping apparatus with arotatable arm of the above character which can perform ablations in thespaces between the arms of the basket assembly.

Additional objects and features of the invention will appear from thefollowing description from which the preferred embodiments are set forthin detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of an endocardial mapping apparatuswith rotatable arm of the present invention.

FIG. 2 is an enlarged view, partially sectioned, and somewhat schematicof the distal extremity of the endocardial mapping apparatus of FIG. 1partially engaging a portion of the wall of the heart.

FIG. 3 is a cross-sectional view taken along the line 3--3 of FIG. 2.

SUMMARY OF THE INVENTION

In general, the endocardial mapping apparatus of the present inventionis for mapping the wall of a chamber of the heart having blood therein.The apparatus includes a flexible elongate tubular member havingproximal and distal extremities and at least one lumen extendingtherethrough. A basket assembly is carried by the distal extremity ofthe flexible elongate tubular member and is movable between contractedand expanded positions. The basket assembly has a plurality of elongateflexible circumferentially spaced-apart arms with joined proximal anddistal extremities and a plurality of longitudinally spaced-apartelectrodes carried by each arm for engaging the wall of the heart. Thearms have spaces therebetween when the basket assembly is in an expandedposition. An elongate flexible rotatable member is rotatably coupled tothe joined distal extremities and is disposed within the basketassembly. At least one electrode is carried by the rotatable member forengaging the wall of the heart. Means is coupled to the rotatable memberfor rotating the member within the basket assembly and for bowing itradially outwardly into a space between the arms so as to engage thewall of the heart along a portion of the length thereof for mappingand/or ablating.

DETAILED DESCRIPTION

More particularly, apparatus 11 of the present invention is for mappingthe wall of a chamber of the heart having blood therein and includes acatheter probe 12 described in detail in copending application Ser. No.08/044,255 filed Apr. 7, 1993. Briefly, catheter probe 12 includes aflexible elongate tubular member or shaft 13 formed of a suitablematerial such as plastic which is circular in cross section and hasproximal and distal extremities 16 and 17 (See FIG. 1). Shaft 13 isprovided with at least one lumen 21, which is circular in cross sectionand extends therethrough from proximal extremity 16 to distal extremity17, and carries a basket assembly 22 at its distal extremity. Basketassembly 22 has a central longitudinal axis 23 and is moveable betweencontracted and expanded positions substantially therealong as shown,respectively, by the dotted and solid lines in FIG. 1.

Basket assembly 22 is provided with a plurality of longitudinallyextending flexible arms 25 which have an outwardly bowed shaped memoryfor expanding the basket assembly into engagement with wall 26 of theheart as shown in FIG. 2. Arms 25 have proximal extremities or endportions 27 which are mounted circumferentially about a tubular memberor mandrel 31 connected to distal extremity 17 of shaft 13 so as to bejoined and distal extremities or end portions 28 which are similarlyjoined by a ring 32 at tip 35 of basket assembly 22. Both mandrel 31 andring 32 are made of any suitable material such as polyethylene orteflon. When expanded, arms 25 are circumferentially and symmetricallyspaced-apart and have a plurality of spaces or openings 33 therebetween.A plurality of longitudinally spaced-apart electrodes 36 are carried byeach arm 31 for engaging heart wall 26 and are electrically coupled to amultiplexer chip 37 for transmitting electrical signals sensed therebyto shaft proximal extremity 16. The arms can also carry a plurality oflongitudinally spaced-apart radiopaque markers or traces, not shown inthe drawings, formed of a suitable material such as platinum or gold topermit fluoroscopic viewing of the basket assembly.

An elongate flexible rotatable member or arm 41 is carried by shaftdistal extremity 17 and by distal end portion 28 of basket assembly 22and can be bowed outwardly from a first position within basket assembly22, as shown in dotted lines in FIG. 2, to a second position inengagement with heart wall 26, as shown in solid lines in FIG. 2. Arm 41is circular in cross section and has a proximal end portion 42 whichrotatably and slidably extends through lumen 21 of the shaft and a bore43 formed longitudinally through the center of mandrel 31. Arm 41 has adistal end portion 46 which rotatably extends through a bore 47 providedin the center of ring 32 and has a retaining ring 50 crimped on the endthereof for rotatably coupling and connecting arm 41 to ring 32, Theinner surfaces forming bores 43 and 47 are circular in cross section andserve as bearing surfaces to facilitate the relative smooth movement ofrotatable arm 41 in mandrel 31 and ring 32.

Rotatable arm 41 has a tube 51 formed of a suitable material such asplastic and provided with a longitudinally extending central bore 52which is circular in cross section and two crescent shaped outer bores53 circumferentially disposed about central bore 52 (See FIG. 3). A coreelement or wire 56 made of any suitable superelastic material extendsthrough central bore 52 to provide rotatable arm 41 with an outwardlybowed shaped memory. Tube 51 has an outer diameter ranging from 0.040 to0.070 inch and wire 56 has a diameter ranging from 0.010 to 0.025 inch.Mandrel 31 and ring 32 can have a longitudinal dimension on the order of0.125 to 0.500 inch.

At least one electrode 57, and as shown four longitudinally spaced-apartelectrodes 57, are carried by rotatable arm 41 for engaging heart wall26. Electrodes 57 are made of any suitable material such as platinum andare generally tubular in shape, being snugly disposed about thecircumference of tube 51. A plurality of lead means in the form ofconductors 61 are disposed within outer bores 53 and are electricallyconnected at one end to respective electrodes 57 by electricalconnectors 62 extending through tube 51 as illustrated in FIG. 3.Conductors 61 extend longitudinally through shaft 13 to proximalextremity 16 thereof. It should be appreciated, however, that conductors61 could be coupled to multiplexer chip 37 and be within the scope ofthe present invention.

Electrodes have a significant mass in comparison to electrodes 36 ofbasket assembly 22 and, in this regard, have a length on the order ofone to three millimeters, an outer diameter on the order of 0.040 to0.075 inch and a thickness of approximately 0.003 inch. It should beappreciated that rotatable arm 41 and electrodes 57 thereon can becooled in the manner disclosed in U.S. Pat. No. 5,348,554 filed Dec. 1,1992 and be within the scope of the present invention. The rotatable armcan also be provided with radiopaque markers or traces of the type andfor the purpose discussed above.

A handle 66 is carried by proximal extremity 16 of shaft 13 foroperating apparatus 11. A torque cable 67 is joined to proximal endportion 42 of rotatable arm 41 and extends through lumen 21 of shaft 13and out the end of the handle so as to be accessible by the operatingphysician. A torque knob 68 is fixed to the accessible end of the torquecable and is included within the means of apparatus 11 for rotating andswinging arm 41 within basket assembly 22 and for bowing arm 41 radiallyoutwardly into an opening 33 between arms 25 of the basket assembly. Aconnector 71 is included on handle 66 and is electrically connected tomultiplexer chip 37 and electrodes 36 of the basket assembly andconductors 61 and electrodes 57 of rotatable arm 41. A power supply, acontroller and a radio frequency generator can be connected to connector71 for operating apparatus 11.

In operation and use, basket assembly 22 can be introduced into aventricle of a heart and operated in substantially the same manner asdiscussed in U.S. Pat. No. 5,279,299 filed Jul. 24, 1992 and U.S. Pat.No. 5,324,284 filed Jun. 5, 1992. Once positioned within the chamber ofthe heart, the operating physician causes basket assembly 22 to expandto a stationary position within the heart so that electrodes 36 thereofengage heart wall 26 for sensing and detecting electrical energy orimpulses therefrom. Simultaneously, the shaped memory of rotatable arm41 causes it to expand to a bowed position and to engage the heart wallso that electrodes 57 can also sense electrical energy from the heartwall.

Once the information regarding heart wall 26 obtained from electrodes 36and/or 57 has been analyzed, the method and apparatus of the presentinvention permit sensing electrical impulses from heart wall 26 in anopening 33 between basket assembly arms 25 where finer resolution to themapping is desired. In this regard, torque knob 68 is pulled outwardlyfrom handle 66 by the operating physician to cause rotatable arm 41 tocollapse within basket assembly 22. The torque knob is then rotated toswing the rotatable arm circumferentially within basket assembly 22 intoregistration with the appropriate opening 33. If the rotatable armengages a protuberance within the heart so as to restrict its rotation,the torque knob can be pulled further so as to cause the rotatable armto become more straightened and thereby avoid the protuberance. Afterrotatable arm 41 has been swung or rotated into registration with thedesired opening 33, torque knob 67 is released slowly to permit therotatable arm to bow outwardly again to its shaped memory configurationand engage heart wall 26 in the opening 33 along a portion of the lengthof the rotatable arm. The circular profile of electrodes 57 increasetheir ability to engage the sometimes irregular shaped heart wall formapping.

Radio frequency energy can also be applied to electrodes 57 for ablatingheart wall 26 in the opening 33. Since electrodes 57 can be directlyconnected to connector 71 without having to pass through multiplexerchip 37, the chip can be simpler in design and less expensive than amultiplexer chip which can accommodate radio frequency energy forablations. The relatively large mass of electrodes 57 reduces the rateof temperature increase and the upper temperature of electrodes 57during ablations and thereby reduces undesirable blood coagulation whichcan be caused by electrodes elevated in temperature to a range of 95° to100° C.

In view of foregoing, it can be seen that an endocardial mappingapparatus having a basket assembly with a plurality of expandable armsfor engaging the wall of the heart and having a rotatable arm which cansense electrical impulses between the arms of the basket assembly hasbeen provided. The rotatable arm can also perform ablations in thespaces between the arms of the basket assembly.

What is claimed is:
 1. An apparatus for mapping the wall of a chamber ofa heart having blood therein comprising a flexible elongate tubularmember having proximal and distal extremities and at least one lumenextending therethrough, a basket assembly carried by the distalextremity of the flexible elongate tubular member and being movablebetween contracted and expanded positions, the basket assembly having aplurality of elongate flexible circumferentially spaced-apart arms withjoined proximal and distal extremities and a plurality of longitudinallyspaced-apart electrodes carried by each arm for engaging the wall of theheart, said arms having spaces therebetween when the basket assembly isin an expanded position, an elongate flexible rotatable member rotatablycoupled to said joined distal extremities and disposed within the basketassembly, at least one electrode carried by the rotatable member forengaging the wall of the heart and means coupled to the rotatable memberfor rotating said member within the basket assembly and for bowing saidmember radially outwardly into a space between the arms so as to engagethe wall of the heart along a portion of the length thereof for mappingand/or ablating.
 2. The apparatus of claim 1 wherein the proximalextremities of the arms are joined about a center and wherein therotatable member has a proximal extremity which is rotatable at saidcenter.
 3. The apparatus of claim 2 wherein said center is provided witha bore extending longitudinally therethrough and wherein the proximalextremity of the rotatable member is slidably disposed within the boreso as to be bowed outwardly from a first position within the basketassembly to, a second position in engagement with the wall of the heart.4. An apparatus for mapping the wall of a chamber of a heart havingblood therein comprising a flexible elongate tubular member havingproximal and distal extremities and at least one lumen extendingtherethrough, a basket assembly carried by the distal extremity of theflexible elongate tubular member and being movable between contractedand expanded positions, the basket assembly having a plurality ofelongate flexible circumferentially spaced-apart arms with proximal anddistal extremities and a plurality of longitudinally spaced-apartelectrodes carried by each arm for engaging the wall of the heart, saidarms having spaces therebetween when the basket assembly is in anexpanded position, an elongate flexible member disposed within thebasket assembly and being circumferentially swingable into registrationwith the spaces between the arms, at least two electrodes carried by theflexible member for engaging the wall of the heart and means coupled tothe flexible member for swinging said member circumferentially withinthe basket assembly and for moving said at least two electrodes into aspace between the arms so as to engage the wall of the heart for mappingand/or ablating.
 5. The apparatus of claim 4 wherein the distalextremities of the arms are joined and wherein the elongate flexiblemember has a distal extremity which is rotatably connected thereto. 6.In a method for mapping the wall of a chamber of a heart with anexpandable basket assembly having a plurality of arms with spacestherebetween disposed in a chamber of the heart in a stationaryposition, the improvement comprising the step of simultaneously sensinga plurality of electrical impulses from the wall in a space betweenadjacent arms.
 7. The method of claim 6 together with the step ofobtaining information regarding the heart from the arms of the basketassembly.
 8. The method of claim 6 together with the step of ablatingthe wall in a space between adjacent arms.